Goldberg Shmuel, Israeli Eran, Schwartz Shepard, Shochat Tzippora, Izbicki Gabriel, Toker-Maimon Ori, Klement Eyal, Picard Elie
Department of Pediatric Pulmonology, Shaare Zedek Medical Center, PO Box 3235, Jerusalem 91301, Israel.
Chest. 2007 Jun;131(6):1747-52. doi: 10.1378/chest.06-2818. Epub 2007 Apr 5.
Asthma prevalence may be reduced in large families. The hygiene hypothesis suggests that older siblings protect their younger siblings from asthma through a modulating effect on the still-maturing immune system. If the hygiene hypothesis is correct, asthma prevalence should be inversely related to birth order. The objective of this study was to examine the relationship between asthma prevalence, and family size and birth order.
The medical records of 531,116 Israeli military conscripts were reviewed. The association between number of children in the family and the prevalence of asthma, and between birth order and the prevalence of asthma was assessed. Odds ratios for asthma by birth order and family size, adjusted for each other, were calculated.
Asthma was diagnosed in 26,833 male subjects (8.6%) and 15,079 female subjects (6.9%). Asthma prevalence was inversely related to the number of children in the family (p < 0.001). Among subjects who were the only child in the family, the prevalence of asthma was 7.3%. The prevalence increased to 8.95% among subjects from families with three siblings, and then progressively decreased as the number of siblings increased, and reached a trough of 0.58% in conscripts from families of 15 to 20 siblings. Asthma prevalence was similar for all birth orders.
In families with four or more children, asthma prevalence is inversely related to the number of children in the family. Asthma prevalence is similar for all birth orders. The similar asthma prevalence for all birth orders challenges the hygiene hypothesis as the mechanism for the decreased asthma prevalence in large families.
大家庭中哮喘患病率可能较低。卫生假说认为，年长的兄弟姐妹通过对仍在发育的免疫系统产生调节作用，保护年幼的兄弟姐妹免受哮喘侵害。如果卫生假说正确，哮喘患病率应与出生顺序呈负相关。本研究的目的是探讨哮喘患病率与家庭规模及出生顺序之间的关系。
回顾了531,116名以色列应征入伍军人的病历。评估了家庭子女数量与哮喘患病率之间以及出生顺序与哮喘患病率之间的关联。计算了经相互调整后的按出生顺序和家庭规模划分的哮喘比值比。
26,833名男性受试者（8.6%）和15,079名女性受试者（6.9%）被诊断为哮喘。哮喘患病率与家庭子女数量呈负相关（p < 0.001）。在独生子女中，哮喘患病率为7.3%。在有三个兄弟姐妹的家庭中，患病率升至8.95%，然后随着兄弟姐妹数量的增加而逐渐下降，在有15至20个兄弟姐妹的家庭中，应征入伍者的患病率降至最低点0.58%。所有出生顺序的哮喘患病率相似。
在有四个或更多孩子的家庭中，哮喘患病率与家庭子女数量呈负相关。所有出生顺序的哮喘患病率相似。所有出生顺序的哮喘患病率相似，这对卫生假说作为大家庭中哮喘患病率降低的机制提出了挑战。
